Safe zone detection system for lift having a pluarlity of sensors

Abstract

A safe-zone sensing system for a lift having a base, a lift platform, and a driving system for raising and lowering the lift platform. The safe-zone sensing system includes a sensor system having a plurality of sensors mounted to the base of the lift. The sensors collectively defining a safe-zone around the base of the lift and detecting motion or obstructions within the safe zone, a controller fires the sensors in a preselected sequence for continuously scanning the safe zone. Scanning is started when the platform raises above a preselected height. The sensor controller generates an alert which initiates a safety sequence when motion or obstructions are sensed by at least one of the plurality of sensors.

What is claimed is: 
     
       1. A safe-zone sensing system for a lift, the lift having a base, a lift platform, and a driving system for raising and lowering the lift platform, the safe-zone sensing system comprising:
 a sensor system comprising a housing containing a plurality of sensors configured to be mounted to a top surface of the base of the lift, the sensors collectively define a safe-zone disposed around the base of the lift and detecting motion or obstructions within the safe zone, a controller fires the sensors in a preselected sequence to continuously scan the safe zone, the scan operation is started when the platform raises above a preselected height, during the scan operation one of the plurality of sensors if motion or an obstruction is detected, the sensor controller generates an alert which initiates a safety sequence when motion or obstructions are sensed by at least one of the plurality of sensors. 
 
     
     
       2. The safe-zone sensing system according to  claim 1  further comprising:
 an alert device which alerts during the safety sequence when motion or obstructions are sensed by at least one of the plurality of sensors. 
 
     
     
       3. The safe-zone sensing system according to  claim 1  wherein the sensor controller is in communication with the drive system of the lift and wherein the controller stops the drive system from further lowering of the platform of the lift during the safety sequence when motion or obstructions are sensed by at least one of the plurality of sensors. 
     
     
       4. The safe-zone sensing system according to  claim 3  further comprising:
 an alert device which alerts during the safety sequence when motion or obstructions are sensed by at least one of the plurality of sensors. 
 
     
     
       5. The safe-zone sensing system according to  claim 1  wherein the sensors are ultrasonic sensors. 
     
     
       6. The safe-zone sensing system according to  claim 1  wherein the height is about 22 inches and the sensor system powers on when the platform reaches the height. 
     
     
       7. The safe-zone sensing system according to  claim 1  wherein the sensor system measures the distance to objects in the safe zone and stores these distances, the sensor system continuously measures the distance to the objects, the measurements are compared to those stored, if an object is determined to have moved closer to the lift or an object is detected that was not previously measured within the safe zone, an alert is triggered and a predetermined sequence of operations is initiated. 
     
     
       8. A lift vehicle comprising:
 a base, a lift platform, and a driving system for raising and lowering the lift platform; and 
 a sensor system comprising a housing containing a plurality of sensors mounted to a top surface of the base of the lift, the sensors collectively define a safe-zone disposed around the base of the lift and detecting motion or obstructions within the safe zone, a controller fires the sensors in a preselected sequence to continuously scan the safe zone, the scan operation is started when the platform raises above a preselected height, during the scan operation one of the plurality of a sensors sends out a signal and the signal is received by another of the plurality of sensors if motion or an obstruction is detected, the sensor controller generates an alert which initiates a safety sequence when motion or obstructions are sensed by at least one of the plurality of sensors. 
 
     
     
       9. The lift vehicle according to  claim 8  further comprising:
 an alert device which alerts during the safety sequence when motion or obstructions are sensed by at least one of the plurality of sensors. 
 
     
     
       10. The lift vehicle according to  claim 8  wherein the sensor controller is in communication with the drive system of the lift and wherein the controller stops the drive system from further lowering of the platform of the lift during the safety sequence when motion or obstructions are sensed by at least one of the plurality of sensors. 
     
     
       11. The lift vehicle according to  claim 10  further comprising:
 an alert device which alerts during the safety sequence when motion or obstructions are sensed by at least one of the plurality of sensors. 
 
     
     
       12. The lift vehicle according to  claim 8  wherein the sensors are ultrasonic sensors. 
     
     
       13. The lift vehicle according to  claim 8  wherein the height is about 22 inches and the sensor system powers on when the platform reaches the height. 
     
     
       14. The lift vehicle according to  claim 8  wherein after power on the sensor system measures the distance to objects in the safe zone and stores these distances, the sensor system continuously measures the distance to the objects, the measurements are compared to those stored, if an object is determined to have moved closer to the lift or an object is detected that was not previously measured within the safe zone, an alert is triggered and a predetermined sequence of operations is initiated. 
     
     
       15. The lift vehicle according to  claim 8  wherein the sensor system is mounted to the base of the lift.